Using 27c800 in a 40 pin socket

[mikey]

Is it possible to use a 27c800 as a 27c400 in a 40 pin socket? I have a bunch of 27c800's kicking around, but need to replace an eprom in a 40 pin socket that calls for a 27c400. Can't you just short the highest address pin to ground or something to make it act as a smaller eprom, almost like you're bankswitching it? Thought I read that somewhere... or maybe I'm crazy...

 

[TerryMathews]

Bend up or clip pins 1 and 42. Align pin 2 on chip into pin 1 on socket.

 

[mikey]

That's it, eh? Is there any need to double up the image when you burn it, or no because the higher address isn't used?

Thanks for the fast reply, btw.

 

[TerryMathews]

That's it, eh? Is there any need to double up the image when you burn it, or no because the higher address isn't used?

Thanks for the fast reply, btw.

I'm glad you said that, I wasn't thinking about how that last address pin would float. Scratch what I said earlier, and bridge it to ground.

Then you don't need to double. If you leave it floating you would need to double as you wouldn't know whether that address line was reading low or high.

 

[mikey]

Awesome, thanks for the help... much appreciated!